Retirement Plans - Funded status of plan by geographic location (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Defined benefit plan
Defined Benefit Plan Disclosure [Line Items]
Funded status - end of year	$ (42,763)	$ (43,843)
US Plan
Defined Benefit Plan Disclosure [Line Items]
Funded status - end of year	(16,306)	(13,124)
UK Plans
Defined Benefit Plan Disclosure [Line Items]
Funded status - end of year	(4,650)	(7,742)
Europe plans
Defined Benefit Plan Disclosure [Line Items]
Funded status - end of year	$ (21,807)	$ (22,977)

The funded status is measured as the difference between the fair value of plan assets and the benefit obligation. Will normally be the same as the net Defined Benefit Plan, Amounts Recognized in Balance Sheet, Total.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=21915240&loc=d3e1703-114919

Name:	us-gaap_DefinedBenefitPlanFundedStatusOfPlan
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant